High Efficiency Internal Combustion Stirling Engine Development P&B Enterprises, Incorporated

Format:

Conference/Event

Author/Creator:

Patton, Patton, author.

Contributor:

Bennett, George

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

A unique engine, based on the regenerative principle, is beingdeveloped with the goal of achieving high brake efficiency over awide power range. It can be characterized as an internal combustionStirling engine (ICSE). The engine is a split-cycle configurationwith a regenerator between the intake/compression cylinder and thepower/exhaust cylinder. The regenerator acts as a counter-flow heatexchanger. During exhaust, the hot gases are cooled by theregenerator. The regenerator stores this heat. On the next cycle,compressed gases flow in the opposite direction and are heated bythe regenerator. The gases coming from the regenerator into thepower cylinder are very hot (~900°C), which provides the necessarygas temperature for auto-ignition of diesel and other fuels.A simplified Air Cycle analysis of the ICS engine is presentedto validate the concept thermodynamics and to show the inherentdifference between the ICS and conventional internal combustionengine (ICE) indicated efficiency. The ICE engine indicatedefficiency increases with increasing compression ratio and isinsensitive to peak temperatures, whereas in the ICS engineindicated efficiency increases with decreasing compression ratioand increasing peak temperature. This engine concept is a candidatefor application of adiabatic engine technology which has beenexplored for many years. With materials that can withstand hightemperatures, brake efficiencies of 60-70% are possible. Low heattransfer is important to the proper operation of the engine.A multi-step cycle computer indicated thermodynamic and fluidflow model of the ICS engine of increasing detail was used duringthe engine development. Finally, detailed perturbation studies wereconducted to fully understand the ICS design sensitivities. Anengine friction model was added to the computer model to be able tocompare estimates of ICSE BSFC and BMEP with ICE engines.Important ICS engine innovations include elimination ofthrottling losses, low friction due to low compression ratio, andvery high air cycle efficiencies (~80%) combined with lowcompression ratio. The engine is designed for the highest possibleefficiencies. In addition to these advantages, the engine hasnearly constant pressure combustion, which should help reduce NOxformation.The major findings were: the ICS engine is more efficient thaneither gasoline or diesel engines over the entire operating rangeespecially at part power. At wide open throttle, an ICS engine ismore efficient than either a gasoline or a diesel engine. Thisadvantage increases at part power. On the negative side, the ICSengine has inherent low power density (volumetric efficiency)because of low compression ratio, late air intake and latecombustion. A prototype engine and a modest engine test dynamometerand instrumentation are nearing completion to demonstrate theP&B Enterprises, Incorporated (PBEI), ICSE concept. The prototype is aretrofitted two-cylinder diesel engine. The prototype uses theexisting engine block, and the crankshaft and camshaft fit intoexisting spaces in the block. Anticipated problems to be addressedwith the prototype engine are starting, combustion characteristics,regenerator temperature control and high turbocharging ratios toachieve reasonable power density

Notes:

Vendor supplied data

Publisher Number:

2011-01-0410

Access Restriction:

Restricted for use by site license